The present invention relates to a telescoping carrier which is suitable for use on a suspended rail system, including a monorail system, such as used in areas of production, including for example body shops, assembly shops, and other assembly or manufacturing facilities.
In conventional production line type facilities, components which are manufactured or assembled, are often required to be moved between stations where various assembly or manufacturing processes are performed on the component. Where large components are handled, such as in an auto assembly plant, often, the components are supported on a rail which runs across the production area floor to permit the components to be transferred between the various stations on the rail. However, depending on the function to be performed at the respective station, the component may require lifting or lowering in order to perform the designated function on the component. Typically, stations that require the component to be raised or lowered are provided with a lift assembly or mechanism which permits the operator of the station to lower and raise the component for performing their specific function. The rail support system, however, occupies a significant amount of space of the production area floor. Further, since each component is lowered or raised when it reaches the respective station, the process of lifting and lowering the product increases the cycle time for the production process. Furthermore, present systems do not provide the flexibility of adding or removing stations without a total overhaul of the whole production line.
Consequently, there is a need for a system which will reduce the cycle time of the production process while providing increased flexibility so that the system can be modified to accommodate an increase, decrease or change in the stations in the production line.
Accordingly, the present invention provides a lift carrier that is adapted for use on a suspended rail system which lowers and raises large components, such as vehicle bodies, in a manner that reduces the process cycle time and, further, in a manner that consumes less floor space. In addition, the lift carrier provides flexibility so that the assembly or manufacturing process can be modified without a complete overhaul of the whole system.
In one form of the invention, a load carrier for supporting, raising or lowering a load includes a frame member, which is adapted to be movably supported by a rail, a telescoping mast, which is supported by the frame member, and a support frame. The support frame is supported by the telescoping mast and is adapted for supporting a load. The telescoping mast includes at least one fixed mast section and at least one movable mast section. The support frame is coupled to the movable mast section, which is supported for movement between a plurality of extended positions in which the support frame is lowered and raised with respect to the frame member and the fixed mast section. The movable mast section is guided by the fixed mast section when the movable mast section is moved to its extended positions. The load carrier further includes a driver which selectively moves the movable mast section to the extended positions and which includes at least one cord for raising and lowering the movable mast section with respect to the fixed mast section and the frame member. The cord is arranged whereby the cord bends in a single direction to eliminate back bending in the cord thereby increasing the longevity of the cord.
In one aspect, the movable mast section includes a lift sheave. The driver includes a cord drum with the cord extending from the cord drum over a redirection sheave down the mast and around the lift sheave. The cord extends from the lift sheave over a second redirection sheave to a cord clamp whereby the cord raises or lowers the movable mast section when the drum rotates.
In other aspects, the fixed mast section includes an interior passageway. The movable mast section is positioned in the passageway and moves through the interior passageway when the movable mast section is moved to its extended positions. Preferably, the movable mast section is guided by a plurality of guide bars when the movable mast section is moved through the interior passageway. In preferred form, the fixed mast section includes a first set of guide bars, with the movable mast section including a second set of guide bars, which guide the movable mast section through the fixed mast section.
In yet further aspects, each of the fixed mast section and a movable mast section includes a corresponding set of guide rollers for engaging the guide bars whereby the guide rollers and the guide bars guide the movable mast section to move to its extended position. For example, the guide bars may comprise cylindrical rods. Preferably, the guide bars are tensioned to reduce play between the movable mast section and the fixed mast section. Preferably, the guide bars are tensioned at their opposed ends.
According to another form of the invention, a load carrier for supporting, raising or lowering a load includes a frame member, which is adapted for being movably supported by a rail, a telescoping mast, which is supported by the frame member, and a support frame which is supported by the telescoping mast. The telescoping mast includes at least one fixed mast section and first and second movable mast sections. The load frame is mounted to the second movable mast section, with the first and second movable mast sections being supported for movement between extended positions in which the support frame is lowered and raised with respect to the frame member and the fixed mast section. The first movable mast section is guided by the fixed mast section, with the second movable mast section being guided by the first movable mast section when the first and second movable mast sections are moved to there extended positions by a driver. The driver moves the first and second movable mast sections to thereby lift and lower the support frame. The first and second movable mast sections are synchronized to move substantially in the same direction at about the same speed by at least one synchronizing cord.
Preferably, the first and second movable mast sections are synchronized to move substantially in the same direction at about the same speed by a pair of synchronizing cords, with one of the cords being coupled to the first and second mast sections, and the other of the cords being coupled to a fixed portion of a load carrier and one of the first and second movable mast sections.
In other aspects, the first and second mast sections are guided along the fixed mast section by a plurality of guide rollers. For example, the fixed mast section preferably includes a first set of the plurality of guide bars, with the first movable mast section including a second set of the plurality of guide bars. The first and second guide bars guide the first movable mast section along the fixed mast section.
In further aspects, the first movable mast section includes a third set of the guide bars, with the second mast section being guided along the first movable mast section by the third set of guide bars. Preferably, the fixed mast section includes a corresponding set of guide rollers for engaging the second set of guide bars of the first movable mast section. In addition, the first movable mast section includes a corresponding set of guide rollers for engaging the guide rollers of fixed mast section to guide the first movable mast section along the fixed mast section. In yet further aspects, the second movable mast section includes a corresponding set of guide rollers for engaging the third set of bars of the first movable mast section. In further aspects, the second movable mast section includes a fourth set of the guide bars with the first movable mast section including a corresponding set of guide rollers for engaging the fourth set of guide bars. It can be appreciated that the first and second movable mast sections are guided as they move between their extended positions in a manner that reduces the play between the movable mast sections and the fixed mast section and further in a manner that results in the movable mast sections moving in substantially parallel directions thus reducing the risk of binding.
According to yet another form of the invention, a load carrier for supporting, raising or lowering a load includes a frame member, a telescoping mast, which is supported by the frame member, and a support frame which is supported by the telescoping mast. The telescoping mast includes at least one fixed mast section and first and second movable mast sections, with the support frame being supported by the second movable mast section. The first and second movable mast sections are supported for movement between extended positions in which the support frame is lowered with respect to the frame member and retracted positions in which the support frame is raised with respect to the frame member. The telescoping mast includes a plurality of guide rods, with the first and second movable mast sections being guided by the guide rods when moved between extended and retracted positions within the fixed mast section. A driver lowers and raises the first and second movable mast sections to thereby lower and raise the load.
Preferably, the guide rods are tensioned to minimize play between the movable mast sections and the fixed mast section. In other aspects, the driver includes at least one cord, which is coupled to the second movable mast section and lifts and lowers the second movable mast section to thereby lift and lower the first movable mast section. Preferably, the first and second movable mast sections are synchronized to move substantially in the same direction at about the same speed. For example, the first and second movable mast sections may be interconnected, such as at least one synchronizing cord, whereby they move substantially in the same direction at about the same speed.
These and other objects, advantages, purposes, and features of the invention will become more apparent from the study of the following description taken in conjunction with the drawings.